Batteries, including lithium-ion batteries, may be used for a variety of target applications that require relatively higher levels of energy storage, power delivery and recharge cycle capability. These applications may include, for example, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), solar/wind (renewable) power smoothing, power grid frequency regulation and power grid storage for peak shaving. Parties, ranging from manufacturers to distributors to end users of these batteries, have an interest in determining the useful life span of the batteries. Unfortunately, the lifespan may vary considerably depending on the target application and in particular the drive cycle of the application, which may include, for example, the depth of discharge and the charge and discharge rates.
Existing battery test procedures are typically application dependent (e.g., drive cycle dependent) and time consuming, sometimes taking a year or more to complete. The tests are therefore expensive and the results from one application specific test procedure may be difficult to apply or convert to another usage scenario.
What is needed, therefore, are improved methods and systems for cycle life testing of batteries that may be performed in a shorter time period and provide measurements useful to characterize a battery for a variety of target usage applications.